US4547962A - Method of making eddy-current probes - Google Patents
Method of making eddy-current probes Download PDFInfo
- Publication number
- US4547962A US4547962A US06/433,294 US43329482A US4547962A US 4547962 A US4547962 A US 4547962A US 43329482 A US43329482 A US 43329482A US 4547962 A US4547962 A US 4547962A
- Authority
- US
- United States
- Prior art keywords
- coil
- profile
- test
- plane
- ferrite core
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
- G01N27/82—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws
- G01N27/90—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws using eddy currents
- G01N27/9006—Details, e.g. in the structure or functioning of sensors
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49002—Electrical device making
- Y10T29/4902—Electromagnet, transformer or inductor
- Y10T29/49073—Electromagnet, transformer or inductor by assembling coil and core
Definitions
- the present invention is concerned with a new method of making eddy-current probes.
- Non-destructive testing of metal parts for the presence of flaws, pits, cracks, etc., by use of an eddy-current probe is now of course a well-established industry.
- Such probes consist for example of a solid cylindrical core of a ferrite material carrying a coil of wire; the impedance of the coil is monitored as the tip of the core is moved over the metal piece under test and flaws, etc. are detected by the change in coil impedance as the tip moves over the flaw.
- a typical size for such a core is about 1.5 mm diameter and the area over which it can detect a flaw is about 2 mm diameter, so that a large specimen must be scanned repeatedly if it is to be examined over its entire surface; such repeated scanning is of course a lengthy and tedious procedure, even when effected automatically by a machine.
- a method of making an eddy-current probe for the scanning of a test surface having a corresponding profile in a plane which intercepts the test surface so as to include the profile including the steps of:
- FIG. 1 is a plan view of an apparatus employing an eddy-current probe of the invention in the testing of a vehicle wheel for defects, such as an airplane wheel,
- FIG. 2 is a enlarged cross-sectional view through the rim of a vehicle wheel to be tested on the apparatus of FIG. 1, and illustrating the use therein of a probe manufactured by the method of the invention
- FIG. 3 is a perspective enlarged view showing a probe of the mounted in a carriage for use in the apparatus of FIG. 1,
- FIG. 4 is a perspective view showing the opposite side of the probe and carriage of FIG. 3,
- FIGS. 5a to 5d are cut-away progressive perspective views to illustrate the method of the invention.
- FIG. 6 is a cross-section through a bellows structure to be tested to show other applications of embodiments of the invention.
- the application of the process of the invention to the non-destructive testing of an airplane wheel has been selected to illustrate the invention, but is not intended in any way to limit the invention, which is of general application to the manufacture of eddy-current probes.
- the invention is particularly suitable for the production of probes intended for the scanning of surfaces that have been generated by a non-flat profile, but it is also suitable for the manufacture of probes intended for the scanning of flat profiles.
- Aircraft wheels are subjected to regular non-destructive testing because of the high stresses to which they are subjected on take-off, landing and particularly taxiing. Under these conditions small flaws such as corrosion pits can lead quickly to the formation of hair-line cracks, which can then develop into major faults resulting for example in parts of the rim breaking away from the wheel.
- a wheel is a particular example of a shape that is generated by a profile, which in this case is rotated about a centre. Other articles can of course be generated as the result of a profile moving in some other mode, such as along a straight line.
- the profile in question is somewhat complex, as will be seen by reference to a section of a wheel section 10 shown in FIG. 2, consisting of a relatively long flat bead seat 12 that is connected by a concave bead seat radius 14 to a bead seat rim 16.
- the wheels of different aircraft types usually have different profiles. Fortunately it is only necessary in practice to examine the bead seat radius and the immediately adjoining portions of the bead seat 12 and bead seat rim 16, but this does require the use of a probe that can scan from the relatively flat bead seat 12 through the seat radius 14 and thence again to the lower part of the convex bead seat rim 16. Such scanning can be performed by a probe 18 manufactured in accordance with the invention and having an active surface 20 that conforms to the bead seat radius and to the immediately adjoining parts 20a, 20b and 20c of the bead seat and bead seat rim.
- the test apparatus illustrated by FIG. 1 consists of a table 22 on which the wheel 10 can be mounted so as to be rotated about a vertical axis 24 by means of a clamp support structure 26 of any convenient form.
- the probe 18 is mounted in a wheeled carriage 28 which is in turn mounted on one end of a universally-movable articulated arm 30 that is spring-biased in any convenient manner to urge the wheeled carriage into engagement with the wheel periphery, so that the carriage will run freely on the wheel periphery, with the probe active surface in close proximity to the wheel surface, as the wheel is rotated about the axis.
- the probe After each complete rotation of the wheel, or progressively as the wheel rotates, the probe is moved vertically by corresponding movement of the arm, so that the entire surface to be examined is scanned by the probe.
- the results of the scan are displayed and recorded by instruments on panel 32.
- test apparatus The exact construction of the test apparatus and the electrical equipment connected to the probe are not important to the description of this invention and are not further described.
- the invention provides a relatively simple and inexpensive method of manufacturing a test probe having an active surface which in this case is convex and conforms sufficiently accurately to the surfaces to be tested.
- the surface 20 has a central convex portion 20b that conforms to the bead seat radius and an end slightly convex portion 20a that conforms to the adjacent part of the bead seat rim sufficiently for the probe to be moved the necessary small amount up that part.
- the other end portion 20c is flat and the probe can therefore be moved along the relatively flat bead seat in order to scan it.
- the probe is made in accordance with the invention by first applying a thin flexible support strip 34 to the profile to be tested, so that the length of the strip is parallel to the plane of the profile and so that the strip 34 assumes the profile required for the probe active surface.
- the strip 34 is simply laid in position on the test surface with its front face contacting the surface, and, if necessary, is tacked in position with a suitable adhesive to facilitate the subsequent steps of the process.
- a flexible test coil 36 is formed, usually by pile winding a plurality of turns of the wire such that the required impedance is obtained and then a portion of the coil of complementary shape to the strip is laid against the back surface of the support strip in the said plane so that the portion also conforms to the profile of the test surface and the support strip 34.
- adhesive is applied to the coil 36 to adhere the windings thereof together; if a slight excess is used this can be used to adhere the coil sector to the support member back surface.
- a second test coil 38 of similar shape to the coil 36 is disposed parallel to the coil 36 but spaced therefrom to provide a balanced electrical circuit.
- This second coil 38 also has a sector complementary portion thereof laid against the back face of the support members so as to conform to the profile in a plane parallel to the plane of the coil 36.
- a plurality of separate ferrite core elements 40 are now inserted within the loops of the coils 36 and 38 so as to extend through both coils transversely to the planes of the two coils, the cores being pressed against the portions adjacent the support member back surface so that together they form an effective electromagnetic ferrite core of shape conforming to the profile.
- the remaining portions of the coils are now pressed into close contact with the respective back portions of the core faces to give a laminated structure for maximum electromagnetic effect.
- the assembly is now surrounded by a rigid metal support frame 42 having terminals 44 for the coil ends and the interior open space filled with an encapsulating resin to hold the assembly firmly in place in the frame.
- the resin has set the probe is removed from the surface and is ready for use, subject only to optional clean-up items such as removal of resin flash and polishing of the front active surface to ensure that it will move easily over the surface to be tested.
- the active surface was formed in contact with the surface to be tested then it has an accurately formed complementary profile. Its mounting in the carriage will usually be such that it is spaced about 0.2 mm from the surface to be tested. Although in this embodiment a non-flat concave profile probe is described it will be apparent that the invention is also applicable to the manufacture of probes for use on convex or flat surfaces, in the latter case the invention providing an extended test surface reducing the number of scans to be employed, without the need for a costly and fragile specially formed unitary ferrite core.
- the total length of the probe active surface was about 5 cm and the support layer was formed from a piece of polyester plastic tape of about 0.075 mm (0.003 in.) thickness.
- Each coil was wound to have an impedance of about 50 ohms at 70 kiloherz, the resulting coils having a cross-section perpendicular to the said plane that is 0.127 mm (0.005 in.) thick.
- the ferrite coils were of circular cross-section of 1.5 mm diameter (0.060 in.) and 6.35 mm (0.25 in.) length, the two coils being spaced about 1.60 mm (0.0625 in.) apart; twenty such cores were used placed with their circumferences touching their immediately adjacent cores.
- cores employed in this embodiment are of circular cross-section
- cores of other cross-sections can of course be used although the circular form has the advantage that the core peripheries can be made to touch one another for magnetic continuity and provide a relatively continuous-appearing surface irrespective of the complexity of the profile, and whether or not it includes convex and/or concave portions.
- FIG. 6 illustrates the complete flexibility of the invention in the manufacture of probes for differing shapes.
- one product requiring testing is metal bellows that in operation are subjected to pressure, mechanical flexing, temperature variations and the like, which can result in the development of cracks and consequent leakage.
- the invention it is possible to provide relatively easily and inexpensively and extremely concave-curved probe 18a and an extremely convex-curved probe 18b which together permit rapid inspection of the surface of the bellows.
- Each probe can have one or more coils, as is required for the test equipment to be employed and in each the ferrite cores can be of any suitable cross-section.
- the choice of core cross-section follows from the desire to provide the maximum amount of core inside the coils, and to this end various shapes can be employed and different shapes may be used at different parts of the same probe.
Abstract
Description
Claims (7)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA000387668A CA1194117A (en) | 1981-10-09 | 1981-10-09 | Method of making eddy-current probes and probes made by the method |
CA387668 | 1981-10-09 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US06736059 Division | 1985-05-20 |
Publications (1)
Publication Number | Publication Date |
---|---|
US4547962A true US4547962A (en) | 1985-10-22 |
Family
ID=4121137
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US06/433,294 Expired - Fee Related US4547962A (en) | 1981-10-09 | 1982-10-07 | Method of making eddy-current probes |
US06/879,513 Expired - Fee Related US4719422A (en) | 1981-10-09 | 1986-06-27 | Eddy-current probes especially for the scanning of non-flat profiled surfaces |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US06/879,513 Expired - Fee Related US4719422A (en) | 1981-10-09 | 1986-06-27 | Eddy-current probes especially for the scanning of non-flat profiled surfaces |
Country Status (2)
Country | Link |
---|---|
US (2) | US4547962A (en) |
CA (1) | CA1194117A (en) |
Cited By (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4694868A (en) * | 1984-12-10 | 1987-09-22 | Siemens Aktiengesellschaft | Apparatus for manufacturing a disc-shaped curved magnet coil |
US4788499A (en) * | 1984-11-19 | 1988-11-29 | Kraftwerk Union Aktiengesellschaft | Method and eddy current test probe for the inspection of screws for nuclear reactor pressure vessels |
US5034737A (en) * | 1988-04-08 | 1991-07-23 | Minelco Inc. | Magnetic flex core mechanism and method for making same |
EP0512796A2 (en) * | 1991-05-06 | 1992-11-11 | General Electric Company | Eddy current probe arrays |
US5262722A (en) * | 1992-04-03 | 1993-11-16 | General Electric Company | Apparatus for near surface nondestructive eddy current scanning of a conductive part using a multi-layer eddy current probe array |
US5526561A (en) * | 1992-04-16 | 1996-06-18 | Gas Research Institute | Method of making an induction heating tool |
WO1999023484A1 (en) | 1997-11-04 | 1999-05-14 | Siemens Aktiengesellschaft | Probe for eddy current testing, method for producing a probe for eddy current testing and method for eddy current testing |
WO1999056124A1 (en) * | 1998-04-27 | 1999-11-04 | Siemens Power Corporation | Eddy current flexible field probe |
US6038760A (en) * | 1994-07-29 | 2000-03-21 | Seb S.A. | Method for making an inductor |
US20040028914A1 (en) * | 2000-11-16 | 2004-02-12 | Hideto Yanome | Water-repellent, oil-repellent and soil resistant coating composition |
EP1577666A1 (en) * | 2004-03-19 | 2005-09-21 | General Electric Company | Method and apparatus for eddy current inspection of a metallic post |
US20110294402A1 (en) * | 2003-07-31 | 2011-12-01 | Miller G Laurie | Eddy Current System for In-Situ Profile Measurement |
WO2019199894A1 (en) * | 2018-04-09 | 2019-10-17 | Jentek Sensors, Inc. | Complex part inspection with eddy current sensors |
CN112362730A (en) * | 2020-11-20 | 2021-02-12 | 西安热工研究院有限公司 | Compressor blade body and blade root rounding array eddy current detection device and method |
Families Citing this family (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4924182A (en) * | 1989-01-09 | 1990-05-08 | The United States Of America As Represented By The Secretary Of The Navy | Eddy current method to measure distance between scanned surface and a subsurface defect |
US4922201A (en) * | 1989-01-09 | 1990-05-01 | The United States Of America As Represented By The Secretary Of The Navy | Eddy current method for measuring electrical resistivity and device for providing accurate phase detection |
USH879H (en) * | 1989-06-30 | 1991-01-01 | The United States Of America As Represented By The Secretary Of The Navy | Method and device for inspecting circumferentially conducting materials |
US5021738A (en) * | 1990-03-26 | 1991-06-04 | The United States Of America As Represented By The Secretary Of The Navy | Field variable, electronically controlled, nested coil eddy current probe |
US5047719A (en) * | 1990-05-25 | 1991-09-10 | The Failure Group, Inc. | Flexible coil assembly for reflectance-mode nondestructive eddy-current examination |
US5315234A (en) * | 1992-04-03 | 1994-05-24 | General Electric Company | Eddy current device for inspecting a component having a flexible support with a plural sensor array |
US5278498A (en) * | 1992-11-06 | 1994-01-11 | The United States Of America As Represented By The Secretary Of The Navy | Surface conforming flexible eddy current probe for scanning varying surface contours |
DE4328712A1 (en) * | 1993-08-26 | 1995-03-02 | Foerster Inst Dr Friedrich | Method and device for testing elongated objects, optionally with cross-section deviating from circularity |
US5442286A (en) * | 1993-09-22 | 1995-08-15 | General Electric Company | Eddy current array inspection device |
US6215300B1 (en) * | 1999-01-14 | 2001-04-10 | General Electric Co. | Eddy current wide probe |
US6741074B2 (en) | 2002-03-01 | 2004-05-25 | General Electric Company | Method and apparatus for separating electrical runout from mechanical runout |
US7312607B2 (en) * | 2004-07-20 | 2007-12-25 | General Inspection Llc | Eddy current part inspection system |
US7633635B2 (en) * | 2006-08-07 | 2009-12-15 | GII Acquisitions, LLC | Method and system for automatically identifying non-labeled, manufactured parts |
US9551689B2 (en) | 2010-02-26 | 2017-01-24 | United Technologies Corporation | Inspection device utilizing eddy currents |
US9646599B2 (en) * | 2013-10-24 | 2017-05-09 | Spirit Aerosystems, Inc. | Remoldable contour sensor holder |
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US3004215A (en) * | 1958-01-27 | 1961-10-10 | Shell Oil Co | Magnetic testing device |
US3304599A (en) * | 1965-03-30 | 1967-02-21 | Teletype Corp | Method of manufacturing an electromagnet having a u-shaped core |
US3378917A (en) * | 1965-04-28 | 1968-04-23 | Chrysler Corp | Induction heating inductors |
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US2265136A (en) * | 1938-06-04 | 1941-12-09 | Walter C Barnes | Flaw detecting apparatus |
US2382857A (en) * | 1943-04-15 | 1945-08-14 | Gen Electric | Electric induction apparatus |
US2885646A (en) * | 1953-04-22 | 1959-05-05 | Kendick Mfg Company Inc | Electrical transformers |
US3535624A (en) * | 1967-06-13 | 1970-10-20 | American Mach & Foundry | Apparatus for inspecting the inside and outside of a tubular member continuously moving in one direction |
FR2111506A5 (en) * | 1970-10-19 | 1972-06-02 | Republic Steel Corp |
-
1981
- 1981-10-09 CA CA000387668A patent/CA1194117A/en not_active Expired
-
1982
- 1982-10-07 US US06/433,294 patent/US4547962A/en not_active Expired - Fee Related
-
1986
- 1986-06-27 US US06/879,513 patent/US4719422A/en not_active Expired - Fee Related
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3004215A (en) * | 1958-01-27 | 1961-10-10 | Shell Oil Co | Magnetic testing device |
US3304599A (en) * | 1965-03-30 | 1967-02-21 | Teletype Corp | Method of manufacturing an electromagnet having a u-shaped core |
US3378917A (en) * | 1965-04-28 | 1968-04-23 | Chrysler Corp | Induction heating inductors |
Cited By (23)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4788499A (en) * | 1984-11-19 | 1988-11-29 | Kraftwerk Union Aktiengesellschaft | Method and eddy current test probe for the inspection of screws for nuclear reactor pressure vessels |
US4694868A (en) * | 1984-12-10 | 1987-09-22 | Siemens Aktiengesellschaft | Apparatus for manufacturing a disc-shaped curved magnet coil |
US5034737A (en) * | 1988-04-08 | 1991-07-23 | Minelco Inc. | Magnetic flex core mechanism and method for making same |
EP0512796A2 (en) * | 1991-05-06 | 1992-11-11 | General Electric Company | Eddy current probe arrays |
EP0512796A3 (en) * | 1991-05-06 | 1993-05-19 | General Electric Company | Eddy current probe arrays |
US5389876A (en) * | 1991-05-06 | 1995-02-14 | General Electric Company | Flexible eddy current surface measurement array for detecting near surface flaws in a conductive part |
US5262722A (en) * | 1992-04-03 | 1993-11-16 | General Electric Company | Apparatus for near surface nondestructive eddy current scanning of a conductive part using a multi-layer eddy current probe array |
US5526561A (en) * | 1992-04-16 | 1996-06-18 | Gas Research Institute | Method of making an induction heating tool |
US6038760A (en) * | 1994-07-29 | 2000-03-21 | Seb S.A. | Method for making an inductor |
WO1999023484A1 (en) | 1997-11-04 | 1999-05-14 | Siemens Aktiengesellschaft | Probe for eddy current testing, method for producing a probe for eddy current testing and method for eddy current testing |
US6452384B1 (en) | 1997-11-04 | 2002-09-17 | Siemens Aktiengesellschaft | Scanning head for eddy-current testing, method for processing a scanning head for an eddy-current test method |
WO1999056124A1 (en) * | 1998-04-27 | 1999-11-04 | Siemens Power Corporation | Eddy current flexible field probe |
US20040028914A1 (en) * | 2000-11-16 | 2004-02-12 | Hideto Yanome | Water-repellent, oil-repellent and soil resistant coating composition |
US20110294402A1 (en) * | 2003-07-31 | 2011-12-01 | Miller G Laurie | Eddy Current System for In-Situ Profile Measurement |
US10105811B2 (en) * | 2003-07-31 | 2018-10-23 | Applied Materials, Inc. | Eddy current system having an elongated core for in-situ profile measurement |
JP2005265848A (en) * | 2004-03-19 | 2005-09-29 | General Electric Co <Ge> | Method and device for eddy current flaw detection inspection for metal post |
EP1577666A1 (en) * | 2004-03-19 | 2005-09-21 | General Electric Company | Method and apparatus for eddy current inspection of a metallic post |
WO2019199894A1 (en) * | 2018-04-09 | 2019-10-17 | Jentek Sensors, Inc. | Complex part inspection with eddy current sensors |
GB2588303A (en) * | 2018-04-09 | 2021-04-21 | Jentek Sensors Inc | Complex part inspection with eddy current sensors |
US11435317B2 (en) * | 2018-04-09 | 2022-09-06 | Jentek Sensors, Inc. | Complex part inspection with eddy current sensors |
GB2588303B (en) * | 2018-04-09 | 2022-12-07 | Jentek Sensors Inc | Complex part inspection with eddy current sensors |
CN112362730A (en) * | 2020-11-20 | 2021-02-12 | 西安热工研究院有限公司 | Compressor blade body and blade root rounding array eddy current detection device and method |
CN112362730B (en) * | 2020-11-20 | 2024-01-23 | 西安热工研究院有限公司 | Device and method for detecting vortex of blade body and blade root rounding array of compressor blade |
Also Published As
Publication number | Publication date |
---|---|
US4719422A (en) | 1988-01-12 |
CA1194117A (en) | 1985-09-24 |
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